The ketogenic diet is a high fat, moderate protein, low carbohydrate eating pattern, which differs from general, healthful eating recommendations. Many nutrient-rich foods are sources of carbohydrates, including fruits, vegetables, whole grains, milk and yogurt. On a keto diet, carbs from all sources are severely restricted. With the goal of keeping carbs below 50 grams per day, keto dieters often consume no breads, grains or cereals. And, even fruits and vegetables are limited because they, too, contain carbs. For most people, the keto diet requires making big shifts in how they usually eat.
For our bodies, a ketogenic diet is actually a partial fast. During a total fast or starvation state, the body has no source of energy. Thus, it breaks down lean muscle mass for fuel. With the keto diet, the ketones provide an alternative source of energy. Unlike a full fast, the keto diet helps to maintain lean muscle mass.